Australian distance runner Patrick Tiernan has insisted there was no way he was going to be stopped making it to the finish of the Olympic 10,000 metres race, despite collapsing twice on the final lap.

Tiernan, in considerable distress, crashed to the floor twice, including a heavy fall in the final straight of the 25th lap, after he hit the wall on a humid Tokyo Friday night - yet, somehow, he still managed to drag himself over the finishing line.

"It's the Olympics and I've been waiting for five years for it," Tiernan said after being given the all-clear following medical attention at the Olympic Stadium.

"It was about 180 to go that I collapsed the first time. You don't stop when you've got 180 metres to go.

"I didn't think I was completely done at that point, so I got up.

"It happened again and I knew I was in trouble. I was so close that you have to will yourself across the line and finish that race.

"I knew it was something I could do and also needed to do."

The 26-year-old Queenslander, the 10,000m national record holder, had bravely stayed with the leading group for the vast majority of Friday's race.

Yet disaster lurked for Tiernan as the pack sprinted away and the battle for medals was played out.

"I think I executed my race plan really well up until 600 metres to go," Tiernan said.

"I just ran out of steam. It is unfortunate because it is the Olympics and you want to perform on that day.

"It was definitely hot. But we had prepared for it coming in with some heat and humidity training for the last three months.

"I thought I was in a really good spot preparing for that.

"But obviously something wasn't right and we'll reassess that going forward."

Tiernan was hailed as a hero by Aussie fans back home on social media after completing the race in 19th place in a season's best 28 minutes 35.06 seconds.

But he reckoned: "It's not the sort of publicity I want and I was hoping I'd be getting after this race.

"It doesn't feel anything heroic to me.

"I just fell a little short of where I wanted to be and haven't had a chance to process any of that.

"I'll decompress over the next couple of days, but I'm glad it's struck a chord with a few people."

Tiernan is also entered in the 5,000m, with the heats to take place on Tuesday.

Ethiopia's Selemon Barega was a surprise winner in 27:43.22, with the minor medals going to world record holder Joshua Cheptegei from Uganda and his countryman Jacob Kiplimo.

AAP